<!DOCTYPE html>
<html>
<head>
    <meta charset="UTF-8">
    <title>Document</title>
    <style>
        
    </style>
</head>
<body>
    
</body>
<script>
    
    function Box(){}
    function Fun(){}
    function Fn(){}

    Fn.prototype = new Fun();

    var box = new Box();
    var fun = new Fun();
    var fn = new Fn();

    console.log( Box.prototype.isPrototypeOf(box) );
    console.log( box instanceof Box );
    console.log("-");

    console.log( Fun.prototype.isPrototypeOf(fun) );
    console.log( fun instanceof Fun );
    console.log("-");

    console.log( Fn.prototype.isPrototypeOf(fn) );
    console.log( fn instanceof Fn );
    console.log("-");
    
    console.log( Box.prototype.isPrototypeOf(fn) );
    console.log( fn instanceof Box );
    console.log("-");

    console.log( Box.prototype.isPrototypeOf(fun) );
    console.log( fun instanceof Box );
    console.log("-");

    console.log( Fun.prototype.isPrototypeOf(fn) );
    console.log( fn instanceof Fun );
    console.log("-");

    console.log( Object.prototype.isPrototypeOf(box) );
    console.log( Object.prototype.isPrototypeOf(fun) );
    console.log( Object.prototype.isPrototypeOf(fn) );
    console.log( Object.prototype.isPrototypeOf(Box) );
    console.log( Object.prototype.isPrototypeOf(Fun) );
    console.log( Object.prototype.isPrototypeOf(Fn) );

    var str = new String("hello");
    console.log( Object.prototype.isPrototypeOf(str) );







</script>
</html>